B9 - INHERITANCE 9.1 - Chromosomes & Genes 1. Define inheritance The transmission of genetic information from generation to generation. 2. Define the terms a. Chromosome as a thread of DNA, made up of a string of genes. b. Gene as a length of DNA that is the unit of heredity and codes for a specific protein. A gene may be copied and passed on to the next generation. c. Allele as any of two or more alternative forms of a gene. 3. Define the terms: a. Haploid nucleus as a nucleus containing a single set of unpaired chromosomes (e.g. sperm and egg). b. Diploid nucleus as a nucleus containing two sets of chromosomes (e.g. in body cells). 4. Describe the inheritance of sex in humans (XX and XY chromosomes). Of the 23 pairs of chromosomes present in each human cell, one pair is the sex chromosome; These determine the sex of the individual; Males have XY, and females have XX.